You may think that you have a lot of time to start thinking about discipline, and if you are thinking about discipline in terms of "time-outs" and taking away toys, then you do.
But discipline isn't really about punishment. Instead, it has to do more with teaching your child how to behave as he grows up. This includes trying to support good behaviors and discourage undesired behaviors. And it includes the overall environment in which you raise your child.
So right now, discipline is just about keeping your child on a regular routine for eating, naps, bedtime, and baths, and responding to your baby's needs.
The American Academy of Pediatrics describes discipline for infants as "passive" discipline, in which parents "provide generally structured daily routines but also to learn to recognize and respond flexibly to the infant's needs."
Even as your baby gets a little older and more mobile and is crawling around, instead of getting in trouble for getting into things, you should get your home well childproofed. That way, he will be able to explore safely without worrying about getting into things that he isn't supposed and to and which can get him hurt.
It also isn't too early to start making a plan for how you will discipline your child as he gets older though. This plan should likely include that you avoid spanking and other forms of corporal punishment, which the AAP describes as "a less effective strategy than time-out or removal of privileges for reducing undesired behavior in children."
Sources:
AAP Policy Statement. Guidance for Effective Discipline. PEDIATRICS Vol. 101 No. 4 April 1998, pp. 723-728.
